The long range goal of this research is to develop the microcantilever platform technology for commercial applications requiring sensitive, specific, quantitative and multiplexed detection of proteins present in complex protein mixtures. Here we propose to develop a microcantilever array device for protein profiling that has application in cancer discovery for therapeutic target identification and validation, pathway mapping, and in cancer diagnosis and therapeutic monitoring. This device consists of arrays of microcantilevers having tethered antibody probes for detecting known proteins. Binding of proteins to the probe layer on the microcantilever causes a characteristic surface stress that actuates microcantilever movement, detected by an optical readout system. Numerous microcantilevers having probes for a variety of proteins can be located in a single microfluidics cell, enabling multiplexed detection without protein tagging. The R&D aims are to determine the most effective chemistries for 1) antibody attachment, and 2) surface passivation, to produce the most sensitive and specific system for detection of analyte proteins. For this Phase I research, three antibody probes will be used to characterize the microcantilever response to various concentrations of analyte proteins alone and when present in complex protein mixtures. PROPOSED COMMERCIAL APPLICATIONS: Microcantilever arrays are a platform technology that has far-reaching potential commercial application. The device for multiplex detection of numerous proteins in complex mixtures of proteins would have widespread application in many areas of biological discovery, therapeutics development, diagnostics and therapeutic monitoring. This technology also has potential as a high throughput screening device for ligand-protein interactions in lead compound identification.